Tropical Storm ESTELLE

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TROPICAL STORM ESTELLE DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP072010
800 PM PDT SAT AUG 07 2010
THE LAST FEW GOES-E VISIBLE IMAGES AND A 2334Z AMSU MICROWAVE PASS
INDICATED A SMALL OVAL CENTRAL DENSE OVERCAST DEVELOPING OVER THE
CENTER OF ESTELLE. OUTER BANDS REMAIN IMPRESSIVE...PARTICULARLY
OVER THE SOUTHWEST QUADRANT...AND THE SATELLITE INTENSITY ESTIMATES
ARE 55 KT FROM BOTH TAFB AND SAB. THEREFORE...THE INITIAL
INTENSITY IS BUMPED UP TO 55 KT. DURING THE NEXT 12-24 HOURS...THE
GLOBAL AND SHIPS MODELS FORECAST AN ENVIRONMENT CONDUCIVE FOR SOME
FURTHER STRENGTHENING...BEFORE THE SOUTHEAST TO EASTERLY SHEAR
INCREASES AND A STABLE AIR MASS INDUCES GRADUAL WEAKENING. THIS
SCENARIO SEEMS REASONABLE BASED ON THE IMPROVING CLOUD PATTERN AND
DIFFLUENT OUTFLOW OVER THE WESTERN PORTION OF THE SYSTEM. THE
OFFICIAL FORECAST FOLLOWS SUIT...IS BASED ON THE INTENSITY MODEL
CONSENSUS...AND SHOWS WEAKENING TO A REMNANT LOW IN 96 HOURS.
THE INITIAL MOTION IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS
TRACK AND A LITTLE SLOWER...280/7...AND IS SUPPORTED BY EARLIER
TRMM...AMSU...AND SSMIS MICROWAVE OVERPASSES. LARGE-SCALE MODELS
SUGGEST THAT THE WESTERN EXTENT OF THE SUBTROPICAL RIDGE TO THE
NORTH OF ESTELLE WILL WEAKEN FURTHER IN RESPONSE TO A DEEPENING
MAJOR SHORT WAVE TROUGH EXTENDING ALONG THE WEST COAST OF THE
UNITED STATES. SUBSEQUENTLY...THE FORWARD MOTION OF THE CYCLONE
SHOULD DECREASE FURTHER...POSSIBLY TO A WESTWARD DRIFT IN 3 DAYS.
AFTERWARD...ALL OF THE DYNAMICAL MODELS SUGGEST THAT THE REMNANT
LOW OF ESTELLE WILL COMMENCE A GENERAL DRIFT TOWARD THE SOUTHEAST
AND EAST WITHIN AN INCREASING SOUTHWESTERLY MONSOONAL FLOW. THE
NHC FORECAST IS BASED ON A MULTI-MODEL CONSENSUS AND CLOSELY
FOLLOWS THE PREVIOUS ADVISORY.
FORECAST POSITIONS AND MAX WINDS
INITIAL 08/0300Z 17.3N 109.4W 55 KT
12HR VT 08/1200Z 17.4N 110.2W 60 KT
24HR VT 09/0000Z 17.5N 111.3W 55 KT
36HR VT 09/1200Z 17.5N 112.3W 50 KT
48HR VT 10/0000Z 17.5N 113.1W 45 KT
72HR VT 11/0000Z 17.5N 114.0W 35 KT
96HR VT 12/0000Z 17.0N 114.5W 25 KT...POST-TROP/REMNT LOW
120HR VT 13/0000Z 16.0N 113.5W 20 KT...POST-TROP/REMNT LOW
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FORECASTER ROBERTS/BEVEN
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